Simulation Of Autogenous Acid Substrate Acidification In Carbonate Reservoirs

Matrix acidizing is the important measures to increase production.But in the situation of high temperature wells, with the conventional design concept to acidification, corrosion cost would be very expensive. The result of conventional acidification couldn’t make satisfaction in this situation. Self-generated acid acidification is the commonly used means of reservoir acidification and superior to the conventional acidification. Self-generate acid acidification don’t have the disadvantage of conventional acidizing, so the acidification can achieve good results.The self-generate acid acidification exists the following problems:self-generate acid acidification often constructed in experience, lack of a reasonable criterion, unable to achieve the optimal acidification effect. The problem is to respond to the unknown of self-generate acid-rock reaction, no reasonable of acid construction parameters, lack of a optimization design method. It is necessary to understand the mechanism of the sel-generate acid acidification and model the acid acidification process to conduct a comprehensive simulation to prediction effect.This paper focuses on the reasonable acidification problem of self-generate acid, make the following study:(1)Through the experiment evaluated the self-generate acid system’s properties, calculated the acid rock reaction kinetics constants. It proved that the self-generate acid have good corrosion resistant and slow down the acid-rock reaction rate.(2)The damage zone is divided into independent units for simulation analysis. Applied the theory of planar radial flow and coupled inhomogeneous damage model with mud cake formation model, considering the heterogeneity of the reservoir and the construction parameters change, the model describe damage degree and the shape of the distribution.(3)Coupling the carbonate acidification model and the self-generated acid acidification equivalent model to construct the the self-generated acid model, then comparing the acidification effect of different construction parameter, guiding the construction.(4)Put forward the self-generated acid matrix acidizing model, include the heterogeneous non-uniform damage model, normal acidification model and self-generated acid model to optimization of construction parameters.The study build a self-generated acid model of include:the laboratory evaluation, reservoir damage model, acidification design simulation, acid teatment evaluation. It can be used for the self-generated acid teatment. This several aspects complete system formed a set of system that can apply to carbonate reservoir self-generated acid matrix acidizing model optimized, applying theory to practical results.